The present invention generally relates to surgical access devices and, more specifically, to kink resistant sheaths having steerable sections that enable the sheaths to access hard-to-reach body cavities and conduits.
Sheaths and catheters have long been used to access body conduits such as the arterial and venous branches of the vascular system, urinary tract, body cavities such as the thorax and abdomen, and hollow viscous organs such as the stomach, intestines and urinary bladder. More specifically, sheaths and catheters have been used for fluid delivery, fluid recovery, implant delivery and for providing an access pathway for an instrument such as an endoscope. However, many endoscopes, for example, are flexible enough to bend but are not steerable or deflectable in a controlled and/or dynamic manner.
For some instruments, steering has been achieved, for example, by “pre-bending” the distal tip of a surgical device before insertion and then rotating the device once it has been inserted and has reached a branch artery inside the body. If the angle of the bend has to be adjusted, then the device may have to be removed, re-bent and reinserted. This results in greater time spent in the body and thereby increase surgery time. Furthermore, since these sheaths and catheters need to navigate many hard-to-reach areas, it follows that they should be as stiff and yet as flexible as possible. It is also useful that the sheaths and catheters are constructed with thin walls to minimize the diameter of the device and to maximize the radii of the internal lumen.
In trying to balance the flexibility and stiffness issues, manufacturers have attempted to use a variety of materials such as vinyl, polyurethane, silicone, natural rubber, polyester and nylon. A drawback with these plastics is they only work well when the wall is sufficiently thick. That is, when the access sheath is constructed with a thin wall made of a plastic or rubber material, the sheath may bend or twist during use. This may result in potential damage as the sharp edge of the kinked sheath may allow an endoscope or other device to complicate the surgical procedure. Moreover, a bent or kinked sheath is useless because it cannot communicate and it does not allow the passage of an instrument. As such, there is a desire in the art for a steerable access sheath that is durable enough to provide sufficient strength and stiffness to be guided through a body cavity or tissue and, at the same time, be flexible enough to perform intricate manipulations through the body cavity or tissue. In particular, it would be desirable to have a steerable access sheath having a thin wall section, a large lumen, an atraumatic distal end and a kink resistant construction.